21816604 has 12 divisors (see below), whose sum is σ = 39839184. Its totient is φ = 10433984.

The previous prime is 21816583. The next prime is 21816623. The reversal of 21816604 is 40661812.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 118477 + ... + 118660.

It is an arithmetic number, because the mean of its divisors is an integer number (3319932).

Almost surely, 2^21816604 is an apocalyptic number.

It is an amenable number.

21816604 is a deficient number, since it is larger than the sum of its proper divisors (18022580).

21816604 is a wasteful number, since it uses less digits than its factorization.

21816604 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 237164 (or 237162 counting only the distinct ones).

The product of its (nonzero) digits is 2304, while the sum is 28.

The square root of 21816604 is about 4670.8247665696. The cubic root of 21816604 is about 279.4231491332.

The spelling of 21816604 in words is "twenty-one million, eight hundred sixteen thousand, six hundred four".